Gerald Ratner’s gaffe, made during a speech in 1991, has gone down in history as one of the biggest corporate mistakes of all time, losing the jewellery tycoon his 2,500 shops and his fortune.

In the speech he made in front of thousands of people at the Institute of Directors event in the Royal Albert Hall, Mr Ratner jokingly derided his company’s sherry decanter as “total crap” and said its earrings were “cheaper than an M&S sandwich, but probably wouldn’t last as long.”

Mr Ratner, who was speaking today to business people at the annual MENTA Business Show at the Apex in Bury St Edmunds, admits that he never imagined his “crass” joke would lead to a public outcry.

It resulted in £500m being wiped from the value of the Ratner Group, which at that time included H. Samuel, Ernest Jones and Leslie Davis as well as Ratners.

“Making that speech was a big honour for me,” he recalls. “They used to ask the most successful businessman, along with politicians – the president of South Africa was there, and so was Norman Lamont, the former chancellor of the exchequer, so for somebody like me - I was only 41 then – it was quite an ordeal.”

Mr Ratner explained that the original speech he’d drafted didn’t include the offending remarks, but after he circulated the speech to his co-directors, one of them suggested adding a couple of jokes in. “I’m not really blaming him – well, I am a bit,” he says. “I used to tell him off a bit, so maybe he was trying to get his own back. It’s easy for us to sit here now and say it was a ridiculous thing to do. But it was supposed to be a joke, and nobody could have known that the press were going to be so disingenuous.

“And we didn’t even have social media then.”

Following the fatal error, Mr Ratner lost his job, became “a bit reclusive”, and watched a lot of Countdown. “My wife threatened to kick me out unless I got a job, so I opened up a health club, which I sold for £4m and then I put that money back into a business launching online jewellery, Gerald Online,” he explained. “Life is full of setbacks, but if I have come back from the worst corporate disaster of all time, then anyone can make a comeback.”

Despite managing to climb back up the ladder to a successful business career, Mr Ratner says “of course” he regrets the gaffe. “It ruined my entire life, I lost everything. But now I am not living this life of pressure and trying to be somebody I am not. Although my business today is nothing like the size of the old one, I do appreciate success the second time around much more, and I am more balanced in terms of not rushing around – I now go on the train like everybody else.

“When you are running a large public company and you are very successful and always in the papers, you are trying almost to act that part out of what they are portraying you to be, which is actually not a great thing to do.”

Mr Ratner believes that as the media increasingly bestows celebrity status on successful entrepreneurs, this puts more pressure on these high profile executives. “They can’t be themselves, that’s the problem.” He points to Alan Sugar as an example of a business personality who has managed to stay true to his roots. “He’s still got the same friends he had when he was young, and he doesn’t try to live that celebrity life – I know he’s got planes, but he’s fairly down to earth and that’s the key.

“Sadly, I probably didn’t do that.”

Mr Ratner’s former business empire is now renamed Signet Group, and is the world’s leading retail jewellery specialist, with a market value of £3bn to £4bn. If he hadn’t made the infamous wisecracks, he believes there’s no reason why he wouldn’t be running it still - “It might even have been more successful now, because quite frankly, the UK division has been ignored, which I certainly would not have done,” he said. “So I would now be running a £5bn or £6bn company.”

Read about Mr Ratner’s views on the challenges facing the UK’s high street brands here.